By: Addison Wylie Edet Belzberg’s Watchers of the Sky is built on perseverance.  It’s the film’s bread and butter. The doc has stories about those who refuse to give up fighting for change.  But, the glue holding these stories together is Raphael Lemkin’s unstoppable mission to invent the word “genocide” and give it a meaning.  His sweat and tears worked hard to urge the UN to consider the heinous act of ethnic cleansing as an…